During the alignment of vehicle wheels, it is important that the steering wheel of the vehicle be in a centered position before the vehicle wheels are aligned into their straight ahead position. Typically, during alignment operations, a vehicle steering wheel is first centered and then the wheels of the vehicle are aligned. If a steering wheel is not in a centered position when the vehicle wheels are aligned, later operation of the vehicle with the steering wheel in a centered position will cause the vehicle to turn because the wheels will not be in straight ahead alignment. Various apparatuses have been proposed or devised for assuring that the steering wheel is in its centered position prior to alignment of the vehicle wheels.
One known device for centering a vehicle steering wheel includes a level and an assembly for engaging the molding of the vehicle windshield. The level is aligned with respect to the steering wheel. If the level does not indicate the correct position, the operator adjusts the position of the steering wheel until the level reads correctly. After a correct reading, the operator can indicate that alignment of the wheels should proceed. The usefulness of this apparatus is limited because it relies on human accuracy for reading the level and adjusting the steering wheel to a correct position. This system also does not prevent human error from allowing alignment of vehicle wheels prior to centering of the steering wheel.
In another known system, an apparatus is provided which is attached to a steering wheel which electronically determines whether the steering wheel is centered. This device is connected by wires to an outside apparatus for communication of the steering wheel position information. The wires used in this device can damage the painted surface of the vehicle and also require either that the window of the vehicle be down or that the vehicle door be open. The wires also add further hardware to the system and present the danger of drive off damage or entanglement with other devices in a manufacturing environment.
Other devices for monitoring steering wheel position are known. For example, Seko, et al., U.S. Pat. No. 4,342,279, Aug. 3, 1982, discloses a device for detecting steering angle and direction. This device includes two contacts which are affixed to a steering column and adapted to be engaged by a movable contact when the steering wheel is turned. Upon contact, a pulse signal is produced and is sent to an electric circuit for detecting rotation.
Yanagishima, U.S. Pat. No. 4,007,357, Feb. 8, 1977, discloses a circuit for detecting relative angular displacement of a steering wheel for use in a safety apparatus to trigger an alarm device in the event of a prolonged absence of steering operation during normal driving conditions. This circuit includes a pair of updown counters which are operated to count up or down in response to the direction of steering movements.
Another electrical circuit arrangement for detecting the relative angular movement of a steering wheel is disclosed in Nishioka, et al., U.S. Pat. No. 3,980,999, Sept. 14, 1976. In this invention, the steering movements of a motor vehicle are translated into an electrical signal which increases voltage as the steering wheel rotates in one direction and decreases as the steering is reversed.
In U.S. Pat. Nos. 3,813,932, June 4, 1974, and 3,889,527, June 17, 1975, to Wallace, steering linkage testing apparatuses are disclosed. These apparatuses are designed to test the play in the linkage between the wheels of a vehicle and the steering wheel. These references describe a device which includes a sensing means for determining movement of a vehicle's wheels and a steering wheel movement indicating means for determining the amount of steering wheel movement which occurs prior to movement of the vehicle's wheels. In U.S. Pat. No. 3,889,527, the steering wheel indicating means attaches to a steering wheel by means of a hanger. The device is further supported on a steering wheel by parallel cross pieces which rest on the front of the face of the steering wheel. The device can be adjusted to different steering wheel sizes by adjusting a slidable plate to which the cross pieces are attached so that the apex of the steering wheel is gripped between the hanger and a bottom support piece which is attached to the upper cross bar.
MacMillan, U.S. Pat. No. 3,091,862, June 4, 1963, discloses a device for positioning the wheels of a vehicle in a straight ahead position so that the steering wheel can then be centered. This invention includes mechanical devices for positioning front and rear wheels in desired positions. The device of MacMillan is intended for use in adjusting the steering wheel position after the alignment of the wheels has been altered from the original factory alignment. U.S. Pat. No. 3,624,915, Dec. 7, 1971, to Wilkerson, also describes a wheel alignment apparatus. The disclosed device includes an improved wheel clamp.
A steering wheel system is described in Yamada, et al., U.S. Pat. No. 4,485,371, Nov. 27, 1984, which provides a driver with a confirmation of the direction of the orientation of the front wheels of a vehicle. This reference describes a unit mounted on a steering wheel and connected to the front wheels by a differential gear reduction mechanism.
Although alignment systems and steering wheel centering systems are known, it would be advantageous to provide a vehicle steering wheel centering device that reduces or eliminates drawbacks that exist in known systems.